This article goes into detail about the concept of gender mainstreaming, analyzing its two basic components: (i) its substantive content that is gender approach, according to which inequality between men and women is a systemic phenomenon whose root would be the gender understood as the social (re) construction of difference between sexes and of the relationships between them; and (ii) mainstreaming as a strategy to achieve equality, a strategy for incorporating the gender equality perspective in all regulations and in all policies (global approach), a strategy that would be complementary not exclusionary of equal treatment and positive action and that would aspire to be particularly incisive for the attainment of the objective referred. Given that the goal of gender mainstreaming is social transformation, changing relationship between the sexes, as well as their social representations and given the great ambiguity that exists about what should be the meaning and the direction of changes, this paper argues that social transformation must go in line to overcome assimilationisme (assuming male models by women) and dualism between women and men, keeping separate and distinct spheres, because they both make impossible to achieve true equality. Social transformation, that needs to include men to change, should be oriented to achieve a positive mixture (a positive form of melding), a new model of society that overcomes androcentrism, because the paradigm of human that is susceptible of universalizing would be not only 'male' values but all the human qualities, skills and possibilities, such as the ones that are part of the 'male' model as the ones that are part of the 'feminine' model, since all of them are human values that any human being can practice. Finally this article highlights the potentialities that holds the Gender Mainstreaming strategy and also its risks and difficulties.